1. Field of the Invention
The present invention relates to composite material containers suitable for transport and storage of liquid food products, household cleaners and other fluent materials.
2. Description of the Prior Art
Utility for the present invention is focused upon recloseable liquid containers in consumer sizes of one to five liters such as is used for milk, fruit juice, bleach, automotive antifreeze and household cleaning chemicals. A considerable portion of the present market demand for such containers is provided by blow molded plastic containers as are represented by those described by U.S. Pat. No. 4,070,429 to A. R. Uhling.
Blow molding is a term of art used to describe the process by which a hollow, tubular parison of hot, viscous thermoplastic polymer is extruded into a recloseable mold cavity. When sufficient parison material is in place within the closed mold cavity and both ends of the parison tube are closed as by pinching, an inflation needle is inserted into the closed parison volume and pressurized gas released therethrough. Expansion of the pressurized gas within the closed parison expands the hot thermoplastic walls of the closed parison against the closed mold walls thereby forming the desired final article shape. So formed, the mold confined thermoplastic article is chilled within the mold to solidification. Thereafter, the mold cavity is opened to release the article so formed.
Generally, this process is practiced with a monolayer thermoplastic parison but multiple layer laminations are known to the art.
Product or contents identification and information is applied after the vessel is formed. This may be by masked exterior spray application or a printed paper label secured adhesively to the exterior article walls. In either case, the graphics field is somewhat limited.
Along a separate line of development, recloseable liquid containers are also made from wax or plastic coated paperboard. These containers are usually flat sided, square sectioned rectangles folded from flat sheet stock. An attractive marketing feature of such containers is the capability of complex graphic presentations printed directly upon the exterior container surfaces before folding. On the negative side, the liquid seal integrity of paperboard containers is less than satisfactory.
It is, therefore, an object of the present invention to combine the superior features of blow molded and paperboard containers without the corresponding negative consequences.
Another object of the present invention is to provide a composite material liquid container having a paperboard exterior structural jacket having preprinted graphics and an blow molded interior liquid seal.
Another object of the present invention is to provide a high production rate composite material bottle that relies upon a minimal quantity of polymer as an interior liquid seal liner.
Another object of the present invention is the provision of a blow molded liquid container having improved rigidity and stiffness.